On the gathering of Tor onion addresses
Javier Pastor-Galindo, Félix Gómez Mármol, Gregorio Martínez Pérez
Abstract
Exploring the Tor network requires acquiring onion addresses, which are crucial for accessing anonymous websites. However, the Tor protocol presents a challenge, as it lacks a standard method for finding these complex links composed of either 16 or 56 base32-coded characters and featuring the unique “.onion” top-level domain. This study delves into the existing literature analyzing onion services and categorizes the various strategies employed to gather their addresses. The success of each approach is measured by the number of addresses obtained, while the relevancy of the work is evaluated by comparing the number of services uncovered to Tor’s official count. The results indicate that the most used techniques are Tor crawling and repositories, whereas the most effective methods are relay injection, repositories, and Tor crawling. This paper also estimates the representativeness of literature collections, revealing that most past works explored a small portion of the Tor network. The study also uncovers the limitations of onion gathering and sheds light on the challenges for future research to provide more representative datasets for dark web exploration.